Hard to say, depends on criterion. Some of the best have been very humble or cheap. One extreme: box of Crackerjacks shared once as the only food available after a long hike. Other extremes: A Hong Kong restaurant 30+ years ago that's a private club, unavailable to the public. Vienna's 5-meals-a-day comfort-food traditions. Traditional & modern menus around Burgundy, e.g. from Meneau and Parra senior. Adventurous extended tasting menus everywhere, like New Orleans, or Manresa in California.

I really wish I could:

Spend more time tasting things and trying restaurants.

My favorite comfort food:

Exactly.

My top 5 favorite restaurants:

By which criterion, please?? (Animal satisfaction, value, technical skill, creativity, etc.). Ranking all restaurants on a single scale is kind of obviously absurd -- like using a single number to sum up a person. Or a wine.

My most tattered cookbooks:

aren't this week's best-sellers. Earlier cookbooks and food writing also reveal ideas to be older than many folks assume. Like US popularization of authentic Sichuan recipes (early 1970s) or of French cooking for US home cooks (repeatedly since early 1800s). French rebellion against thickened sauces (1800). Wide range of greens and herbs for salads (1600s).